Better comments. Move inner classes to end

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1478062 13f79535-47bb-0310-9956-ffa450edef68
Wire in flushBuffer()

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1478063 13f79535-47bb-0310-9956-ffa450edef68